Meraki Alerts Client IP conflict

[VEsterly135]

I never had alerts coming to me as much as this year.. And trying to find out what might the issue:

I have DHCP running on my firewall: 

- it is set with Routed (mode)

- Client Tracking (Mac Address: Default)

- Lan Config of 192.168.1.0/23

The Alerts I am getting are the following: 

The security appliance in the  03-firewall network has detected an IP conflict with two or more devices.

The IP 192.168.0.245 is claimed by clients with the following MAC addresses: 

- Cisco Meraki

When I click the Mac Addresses one is showing the client the other is not, what could be causing this to happen, what could i do to remove these alerts. Am i running out of IP's?

[Rebry]

Hi VEsterly135

If the device you're seeing is an iOS device, it might be because of mac address randomization from Apple:

To reduce this privacy risk, iOS 14, iPadOS 14, and watchOS 7 use a different MAC address for each Wi-Fi network. This unique, static MAC address is your device's private Wi-Fi address for that network only.

https://support.apple.com/en-us/HT211227

[Bruce]

It is not really because of the MAC randomisation as such. Apple introduced a bug with this feature such that iOS responds to an ARP with the real MAC sometimes as well as the randomised MAC, which is what produces the error on the MX. Supposedly this will be fixed in the next iOS update.

[Jwiley78]

Never heard of this before.  I've actually got to the point of turning the alerts off because it was a nuisance.